In SMT chip processing, we often use flux. What is flux? We know that in the welding process of SMT chip processing, it is necessary to clean the electric welding welding metal material and electric welding welding surface. In this process, the raw material of auxiliary components and solder paste is flux. It is mainly composed of additives, rosin, activator, film-forming agent, solvent and so on.

So, what are the specific functions of flux in SMT processing? The following Sanjing will give you a brief introduction:

①Remove oxides or other contaminants on the soldering surface of the SMT patch. The rosin acid in the flux can undergo a reduction reaction with the oxide film on the surface of the metal to be welded; the active agent in the flux reacts with copper oxide to finally replace pure copper; the metal salt in the flux is replaced with the oxide on the surface of the metal to be welded Reaction: The organic halides in the flux can also react with the surface of the welded metal to remove oxides.

②Prevent the re-oxidation of the solder and the soldering surface during SMT chip processing and soldering. During soldering, the flux covers the surface of the welded metal and solder, which isolates the surface of the welded metal and solder from the air, which can effectively prevent the metal surface from being oxidized again at high temperatures.

③Reduce the surface tension of molten solder and promote the expansion and flow of solder. A certain chemical reaction occurs when the soldering flux removes the oxide on the soldering surface, which can reduce the surface tension and viscosity of the molten solder, while increasing the surface activity, thereby improving the wettability of the solder.

④ Facilitate the transfer of heat to the welding area. The flux reduces the surface tension and viscosity of the molten solder, increases the fluidity of the liquid solder, and facilitates the rapid and effective transfer of heat to the soldering area.

The above is the role of flux in SMT processing. It can be seen that flux is indispensable in PCBA processing. Reasonable use of flux can ensure the quality of electronic OEM processing.